The present disclosure provides an antenna system, including: a metal housing including a radiation frame and a grounded back shell; a circuit board located in the metal housing and including a radio frequency feeding source and a tunable capacitor; and an antenna unit connected to the radio frequency feeding source and configured to be coupled to the radiation frame. A fracture is formed between each of two ends of the radiation frame and the grounded back shell. The tunable capacitor is connected to the radiation frame so as to change an electrical length of the antenna system by switching to different capacitances. Compared with the related art, the antenna system provided by present disclosure, by providing the tunable capacitor as a tuner of the antenna system, not only can achieve that the radiation frequency of the antenna system covers 790-960 MHz and 1710-2690 MHz, but also has good radiation performance.